To be honest, it all depends on turnout/coattails. If GOP turnout is good, and Trump has serious coattails.... pick up of 3 to 4. That would be the best-case scenario, in my opinion.
Would be great to see that AND a Trump win...Clarence Thomas could then retire and be replaced with another pro-Constitution Justice.
Senate
https://www.270towin.com/2024-senate-election/
House
https://www.270towin.com/2024-house-election-predictions/